In a conventionally known robot zero-point calibration device (as described, for example, by Japanese Unexamined Patent Application, Publication No. Hei 6-134683, for example) configured to calibrate a zero point of a robot, the robot is manually put into such a position by a worker that a predetermined positional relation is achieved between a calibration jig attached to a wrist flange of the robot and a calibration jig attached to a base of the robot. The worker performs this positioning while checking a plurality of dial gauges indicating an interval between calibration jigs. Then, the position of the robot is reflected on a predetermined position of each axis of the robot.